The textile industry, which produces toxic and low biodegradable wastewater, is a major industry of Taiwan. Thus, this study compared the performance of the membrane bioreactor (MBR) and sequencing batch reactor (SBR) process for treating real textile dyeing wastewater. The microbial diversity of the MBR process was also identified by a combined culturing method and molecular biotechnology. The results show that the removal efficiencies for color, COD, BOD, and SS with the MBR process were 54, 79, 99, and 100%, respectively, all higher than the corresponding parameters for the SBR process: 51, 70, 96, and 60%. All the above four parameters for the MBR effluent meet the criteria of the Taiwan EPA, while on the other hand for the SBR process, only color and COD meet the Taiwan EPA effluent criteria. Furthermore, the genus Microbacterium, especially the Microbacterium aurum, was the most predominant population, contributing 70.6% of the total isolates, and might be responsible for the degradation of the dyeing wastewater. Another two textile dyeing degradation bacteria, Paenibacillus azoreducens and Bacillus sp., as predominant bacteria in MBR sludge, were also observed.